But wait, with this system the infected ones have to voluntarily reveal their ID, otherwise nobody knows what their ID are. So how is "We know ID .... is infect

But wait, with this system the infected ones have to voluntarily reveal their ID, otherwise nobody knows what their ID are. So how is "We know ID .... is infected but we have no idea who they are" possible? edit: and no, the observable "ID" is not fixed, so you can't link two unknown IDs.